Tumor-specific T cell based immunotherapies, including therapies employing engineered T cells, have been investigated for anti-tumor treatment. In some cases the T cells used in such therapies do not remain active in vivo for a long enough period. In some cases, the tumor-specificity of the T cells is relatively low. Therefore, there is a need in the art for tumor-specific cancer therapies with longer term anti-tumor functioning.
Malignant gliomas (MG), which include anaplastic astrocytoma (AA-grade III) and glioblastoma (GBM-grade IV), have an incidence rate of approximately 20,000 new cases diagnosed annually in the United States. According to the American Brain Tumor Association total prevalence of individuals living with a malignant brain tumor, based on United States 2010 census data, is roughly 140,000 persons. Although MG is a rare disease, it is highly aggressive and heterogeneous with respect to its malignant behavior and nearly uniformly lethal. Current standard-of-care therapies for high-grade MG yield only short term benefits, and these brain tumors are virtually incurable. Indeed, even with modern surgical and radiotherapeutic techniques, which often exacerbate the already severe morbidities imposed by location in the central nervous system (CNS), the 5-year survival rates are quite low. Furthermore, for the majority of patients who relapse with disease, there are few therapeutic options. Thus, there is a significant need for more effective therapies, particularly for those patients that have recurred/progressed following frontline therapies, and participation of this patient population in clinical trials is warranted.
Adoptive T cell therapy (ACT) utilizing chimeric antigen receptor (CAR) engineered T cells may provide a safe and effective way to reduce recurrence rates of MG, since CAR T cells can be engineered to specifically recognize antigenically-distinct tumor populations (Cartellieri et al. 2010 J Biomed Biotechnol 2010:956304; Ahmed et al. 2010 Clin Cancer Res 16:474; Sampson et al. 2014 Clin Cancer Res 20:972; Brown et al. 2013 Clin Cancer Res 2012 18:2199; Chow et al. 2013 Mol Ther 21:629), and T cells can migrate through the brain parenchyma to target and kill infiltrative malignant cells (Hong et al. 2010 Clin Cancer Res 16:4892; Brown et al. 2007 J Immunol 179:3332; Hong et al. 2010 Clin Cancer Res 16:4892; Yaghoubi 2009 Nat Clin PRact Oncol 6:53). Preclinical studies have demonstrated that IL13Rα2-targeting CAR+ T cells exhibit potent major histocompatibility complex (MHC)-independent, IL13Rα2-specific cytolytic activity against both stem-like and differentiated glioma cells, and induce regression of established glioma xenografts in vivo (Kahlon et al. 2004 Cancer Res 64:9160; Brown et al. 2012 Clin Cancer Res 18:2199).